MLT cooling during stratospheric warming events

Abstract

MLT (Mesosphere and Lower Thermosphere) airglow emission rates and temperatures have been monitored with a Spectral Airglow Temperature Imager (SATI), operated at Resolute Bay (74.68°N, 94.90°W). The 2001/2002 winter season data exhibits a major cooling event for both the O 2 and OH emissions near the end of December, a mild event in mid February and a final cooling in early March. These temperature perturbations are compared with the UKMO stratospheric assimilated data for the Resolute Bay location and for zonally averaged data at 75°N, at two pressure levels, 3.16 hPa and 0.316 hPa. For the major event the 3.16 hPa zonally averaged temperature coincides in time with the MLT cooling. The O 2 temperatures increase slightly, prior to the stratospheric warming, but after onset both emissions exhibit cooling; this is consistent with the TIME‐GCM/CCM3 predictions for the meridional circulation at high latitudes.